Air cleaner



pt.. i3, E93. W. w. LQWTHER AIR CLEANER Filed April 13, 1955 Patented Sept. 13, 1938 PATENT OFFICE AIR CLEANER Wilfred W. Lowther, Minneapolis, Minn., assig'nor to Donaldson Company, Inc., St. Paul, a corporation of Minnesota Application April 13, 1935, Serial No. 16,189 l 14 Claims.

My present invention relates to air cleaners and has for its object to improve the same in various important particulars, whereby eiciency of the same is increased and rendered dependable and reliable, regardless of varying low of air through the air cleaner. The air cleaner is especially adapted for `use in connection with internal combustion engines. The improved air cleaner is of a compact formation, has no parts to get out of order or require frequent cleaning, and has been found highly eicient When used in connection with the internal combustion engines of automobiles designed to run at very high as well as low speeds. A commercial form of the l5 improved air cleaner is illustrated in the accompanying drawing, wherein like characters indicate like parts throughout the several views.

.Referring to the drawing:

Fig. 1 is a view partly in elevation, but chiefly 29 in vertical axial section showing the improved air cleaner;

Fig. 2 is a fragmentary plan view of the air cleaner, some parts being broken away;

Fig. 3 is a fragmentary section taken on the line 3--3 of Fig. 2;. and

Fig. 4 is a horizontal section taken on the line 4--5 of Fig. 1, some parts being broken away.

Carburetors used in connection with internal combustion engines, such, forfexample, as the Ford automobile engine, have air intake tubes. to which the air cleaners are adaptedfto be attached. For attachment to such vcarburetor air intake tubes, the present air cleaner isf provided with an axial clean air discharge tub`e 5 which,

g5 as shown, is provided at a point considerably above its lower end with a secured inner flange 6 that holds a pliable gasket 'i adapted to rest upon the intake tube of the carburetor when the latter is telescoped into the lower end of the tube 5. An annular plate 8 is secured to the lower portion of the tube 5, at a point above its lowerl end, and inclines radially outward and down-I ward and at its outer portion is provided with` an upstanding iiange or inverted skirt 9. This 4B bottom plate and its ilange afford an oil well.

The topl of the air'cleaner is closed by a hoodforming plate I0 that is rigidly but detachably secured, by a nut-equipped stud I I, to a cross bar I2 which, in turn, isk rigidly secured within and 50 extends diametrically of the upper portion of the tube 5.

Preferably, and as shown, the under surface of this hood forming plate III is provided vwith a silencing lining I3 held in place by a woven wire B5 -frame Ill. An approximately cylindrical inner (Cl. 18S-15) skirt I5 is secured at I6 to the outer portion of the hood I Il and depends within the outer skirt or flange 9 from which it is inwardly spaced, so as to leave an annular air-intake passage Il that leads to the outer portion of the oil well I8. 5

An annular baille plate I9 having large air passages 20,- is secured to the upper portion of the vair tube 5 and its outer portion is secured to the upper edge of the inner skirt `I5 and to the outer portion of the hood I 0, as shown, by 10 crimped portion IGI The egxtreme outerfportion of the hood I0 is shown as extended at 2I to form an eave that projects over the upper edge of the outer skirt and the upper edge of the latter is shown as inwardly curved at 22; but neil5 ther the feature of the interlocking crimp I6, the projecting eave 2l or the inturned edge 22 constitute a feature of my present invention. In the drawing, a sleeve 23 is secured around the air delivery tube 5, but this also is not a feature of 20 my invention.

The annular space between the air discharge tube and the inner skirt I5 is filled in by an oil and dust-intercepting device, which is shown as formed by Wire screens y, and is preferably of the 25 character disclosed and claimed in Fthe William H. Schulz Patent No. 2,011,303 issued August 13, 1935, under the title of Air cleaner screen.

As an important feature of this invention, the oilwell I8 is provided with. 'an upstanding cup- 30 forming flange 24 that is located inwardly from the lower edgeof the inner skirt I5 and below the screens. This ange I4 is perforated preferably by circumferentially spaced oil passages 25, for an important purpose which will appear in 35 the description of the operation.

Operation Under vthe suction produced by the engine to which the cleaner is applied, partial vacuum or o suction will be produced in the axial air delivery tube 5 and this will cause a flow of air to the air cleaner, first downward through the annular air intake passage I1, thence to the outer portion of the oil well, and from thence over the upper edge of the cup-forming flange 2l up through the oil and dust-intercepting screens and thence to lthe engine through the air delivery tube 5.

'I'he air thus delivered against the surface of oil in the outer portion of the oil well will lift a large part of the oil in the well out of the cup formed by the ange 24 into the screen chamber in the form of a fine spray. Part of this oil sprayed into the screen chamber will be deposited on and held in suspension by the`screens, and

oil released from the air in the screen chamber in excess to the amount held in suspension by the screens will flow back through the screens chiefly into the cup formed by the bottom plate and flange 24 and will not only illl the cup, but will build up a head of oil above the upper edge of the cup flange 24. The head of oil thus built up above the flange 24.will, particularly at relatively low air velocities, outwardly overflow the upper edge of the cup flange 24 and be picked up by the air passing the upper edge of the cup flange, thereby tending to keep the incoming air stream supplied with oil.

It is here important to note that, during the operation of the cleaner, the amount of oil lifted out of the portion of the oil well radially outward of the cup flange 24 by the incoming air and the amount of oil remaining in the cup will depend largely on the velocity of the air, but the oil remaining in the cup will usually be at a level below the cup flange passages 25. Hence, it will be seen ated some place between three-quarters full load and full load, and that for a period there will be substantially no movement of either air or oil through the passages 25, but that under further increased load and consequently increased air velocity the pressure outward of the cup flange becomes so great that air passes inwardly through the passages 25 and bubbles up through the annular head of oil. This action has been found to be highlyl important for the reason that a point is reached near maximum engine speed or load where the air flowing past the upper edge of the cup flange is at such great velocity and is so steady, and the air pressure above and outward of the cup ange is so relatively great that the oil remains banked up in a head above and inward of the cup flange and practically ceases to overflow the edge of the cup. Now, it will be obvious that in the absence of the passages 25,

- this failure of the oil to enter the air stream that air at any given velocity having once lifted a certain amount of oil out of that portion of the oil well outward of the cup flange 24 will thereafter pass over the upper surface of such oil as remains in the cup and will pass the passages 25 and the upper edge of the cup flange 24 carrying with it little, if any, oil from the bottom portion of the oil cup outward of the flange. Particularly in the lower speed ranges oil is supplied to the air stream passing the upper edge of the cup by oil overflowing the upper edge of the cup and by oil which will spout through the metering passages 25 in the cup ange. Under these conditions, of course, a large part of the.

dust in the air and all of the heavier particles of dust will be thrown directly into such oil as remains in the portion of the cup outward of the flange, but such dust as is carried by the upper edge of the flange will be sprayed with oil and drained back into the oil well cup flange.

AThe oil spray or mist will be carried through the screen chamber to a varying extent depending upon the air velocity through the cleaner, but will all .be removed from the air before the air reaches the discharge tube 5. Under the above described action, there is a continuous flow of oil outwardly into the air stream passing the upper edge of the cup from where it is carried in the form of 'a spray into the screen chamber and when liberated from the air and screens, is returned back by gravity to the oil well radially inward of the by overflowing the upper edge of the cup flange under `conditions encountered near maximum load would result in rapid starvation of the screens u, and great loss in air cleaning eiliciency if operation near maximum engine load or speed were continued for an extended period. However, when the passages 25 are provided, the outward movement of air through the passages does, in bubbling through the annular head of oil, raise some of the oil into the path of rapidly expanding air above and inward of the cup flange, and this oil is delivered to the screens y in sufficient quantities to retain the efficiency of the cleaner during prolonged periods of operation near maximum load. There is little danger in getting an oversupply of oil from this source due to the relatively small volume and low velocity of air passed through the passages 25, and the relatively low velocity of the main air stream at points where it intercepts the oil raised by the airfrom the passages 25.

In order to obtain the desirable functions and efllcient operation described above, the followlng enumerated features are'important, to wit:

cup-forming flange. 'The above described outward flow of `oi1 through the perforations 25 in the cup flange is brought about largely as a result.

of the weight of the head of oil in and above the cup flange.

When the engine is idle, the oil will settle back into the oilwell and cup to a normal altitude which will usually be approximately the lower portions of the screens or the upper edge of the flange 24. The inclined bottom of the cup-forming flange 24 insures delivery of oil outward through the ports 25 even when a large body'of oil is being suspended in the screens. Obviously, by the action of the oil, which is spread over the `screen surfaces, all the dust will be-intercepted and taken up by the oil and caused to flow with the oil back to the bottom' of the well.

Under certain conditions it has been found that oil will cease to flow outwardly through the passages 25 in the cup flange when the air velocity through the cleaner becomes relatively great,l such, for example, as might exist when the engine to which the cleaner is connected is oper- (l) that the annular air intake passage I1 have substantially complete annular communication with that part of the oil well inward of the inner skirt I5; (2) that the inner skirt and cup-forming ang'e each terminate in approximately the same plane and approximately at the static oil level in the well.

From the foregoing, it will be understood that the preferred form for commercial device illustrated in the drawing is capable of various modications within the scope ofthe invention herein disclosed and claimed.

Certain of the features of the air cleaner above described and particularly the relative arrangement of the upper structural features of the air cleaner are not by me herein claimed per se, the

same being the invention of Frank A. Donaldson, f

disclosed and claimed in an application filed by him as inventor of even date herewith, which has matured into Patent No. 2,053,603, dated Sept. 8, 1936.

What I claim is:

1. An air cleaner comprising an axial air discharge tube, an oil-well-forming bottom plate extended outward from lower part of axial air discharge tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from said outer skirt and bottom plate to form an annular air intake passage, anv air pervious oil and dust intercepting means in the space between the axial tube and-inner skirt, and a hood extended over the upper end of said axial Vdischarge tube and intercepting means andkconnected to the upper edge of said inner skirt, and an upstanding cup-forming flange on'said bottom plate of less diameter than the oil well formed by said bottom plate and over the upper edge of which the dust-laden air is passed on its way to said intercepting means, said bottom plate being declined radially outward from said axial tube to its point of connection with said cup-forming flange.

2. An air cleaner comprising an axial air @discharge tube, an oil-well-forming bottom plate extended outward from lower part of axial air delivery tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from said outer skirt and bottom plate to form an annular air intake passage, an air pervious oil and dust intercepting means in the space between the axial tube and inner skirt, and a hood extended over the upper end of said axial tube and intercepting means. and connected to the upper edge of said inner skirt, and an upstanding cup-forming flange on said bottom plate of less diameter than the oil well formed by said bottom plate and over the upper edge of which the dust-laden air is passed on its way to said intercepting means, said bottom plate being declined radially outward from said axial tube to its point of connection with said cup-forming flange, said cup-forming flange having circumferentially spaced perforations below its upper edge.

3. In an air cleaner, a casing provided with an oil well in its lower portion and having an axially located clean air outlet duct leading downwardly from the upper portion of the casing and having outwardly spaced therefrom an annular intake duct arranged to discharge into the outer portion of the well, and a cup-forming ange located in the oil well radially intermediate the axial discharge duct and the inner wall of saidannular air intake duct'to provide with said inner wall a reversely directed continuation of said intake duct, there being a radial passage-way between said duct portions for a substantial circumferential extent at substantially the normal static fluid level in said well, the arrangement of parts being such that, under normal operation of the cleaner, the air discharged into the oil well from the annular intake will impinge upon oil in the well and pass over the surface of such oil as remains in that ,portion o f the oil well radially intermediate the cup-forming ange and annular intake and will then pass/ over the upper edge of said cup-forming flange.

4. The structure defined in claim 3 in which the said cup-forming flange is provided with circumferentially spaced perforations intermediate its upper and lower edges.

5. An air cleaner comprising an axial air discharge tube, an oil-well-forming bottom plate extended outward from the lower portion of said air discharge tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from the said outer skirt and bottom plate to form an annular air intake passage, and a hood extended overand in spaced relation to the upper end of said axial discharge tube and connected to i the upper edge of said inner skirt to close the top thereof, and an upstanding cup-forming ange on said bottom plate of lessdiameter than the oil well'iormed by said bottom plate and over the upper edge of which dust-laden air is passed on its way from the oil well to the axial outlet tube, said bottom plate being declined radially outward from said axial tube to its point of connection with said cup-forming ange.

6. An air cleaner comprising an' axial air discharge tube, an oil-well-forming bottom plate extended outward from the lower portion of said air discharge tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from the said outer skirt and bottom plate to form an annular air intake passage, and a hood extended over and in spaced relation to the upper end of said axial discharge tube and connected to lthe upper edge of said inner skirt to close the top thereof, and an upstanding cup-forming flange on said bottom plate of less diameter than the oil well formed by said bottom plate and over the upper edge of which dust-laden air is passed on its way from the oil well to the axial outlet tube, said bottom plate being declined radially outward from said axial tube to its point of connection with said cup-forming flange, said cup-forming flange having circumferentially spaced perforations below its upper edge.

'7. An air cleaner comprising an axial air discharge tube, an oil-well-forming bottom plate surrounding and extending outwardly from the lower part of the air discharge tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from said outer skirt and bottom plate to form an annular air intake passage for directing air downwardly into the oil well,said annular intake passagebeing in substantially complete annular communication with that portion of the oil well directly inward of the inner skirt, a head closing the upper end of the said inner skirt and being spaced from the open upper. end of the discharge tube, and a cup-forming flange extended upwardly from the bottom plate, said cup-forming fiange surrounding the discharge tube and being spaced radially therefrom and the inner skirt,'said depending inner skirt and cup-forming flange terminating in approximately the same plane.

8. In an air cleaner, a casing provided with an oil well in its lower portion and having an axially located clean air outlet duct leading downwardly from the upper portion of the easingand having outwardly spaced therefrom an annular intake duct arranged to discharge into the outer portion of the well, the bottom of said oil well beingimperforate, and an upstanding annular cup-forming iiange seated on the imperforate bottom of the oil well in radially spaced concentric arrangement with respect to the said clean air outlet duct and annular intake duct, said cup-forming flange terminating with its upper edge substantially opposite the uppermost point of communication between the annular air intake and that portion of the oil well intermediate the annular air intake and said cup-forming fiange.

9. An air cleaner comprising an axial air discharge tube, an oil-well-forming bottom plate surrounding and extending outwardly from the lower part o-f the air discharge tube and provided at its outer edge with an inverted outer skirt, an inner skirt spaced from said outer skirt and bottom plate to form an annular air intake passage` for directing air downwardly into the oil well, said annular intake passage being in substantially complete annular communication with that portion of the oil well directly inward of the inner skirt, a head closing the upper end of the inner skirt and being spaced from the upper end of the discharge tube, and a cup-forming iiange extended upwardly from the bottom plate, said cup-forming fiange surrounding the discharge skirt, an inner skirt spaced from said outer skirt and bottom plate to form an annular air intake passage for directing air downwardly into the `oil well, said annular intake passage being in substantially complete annular communication with that portion of the oil well directly inward of the inner skirt, a head closing the upper end of' the said inner skirt and being spaced from the open upper end of the discharge tube, and a cup-forming flange extended upwardly from the bottom plate, said cup-forming flangesurrounding the discharge tube and being spaced radially therefrom and the inner skirt, said depending inner` skirt andy cup-forming flange terminating in approximately the same` plane, and in which the said cup-forming flange is circumferentially perforated intermediate its upper and lower edges.

11. In an air cleaner, a casing provided with an oil well in its lower portion and having a clean air outlet leading from the upper portion thereof and having adjacent the. interior of the outer wall thereof an annular intake duct arranged to discharge downwardly into the outer portion of the well, and a cup-forming flange located in the oil well radially inwardly of the annular air intake duct, to provide therewith a reversely directed continuation thereof, there being a radial air passageway between said duct portions for a substantial circumferential extent and at substantially the normal static fluid level in said well, the arrangement of parts being such that. under normal operation of the cleaner, the air discharged into the oil well from the annular intake will impinge upon oil in the well and pass over the surface of such oil as remains in that portion of the oil well `radially intermediate the cup-forming flange and annular intake and will then pass over the upper edge of said'cup-forming flange. v

12. The structure defined in claim 11, in which the said cup-forming flange is provided with circumferentially spaced perforations intermediate its upper and lower edges.

13. In an air cleaner, an outer annular casing wall having a closed bottom providing an oil well,

an annular inner wall concentrically disposed within the cuter wall and being closed at its top and open at its bottom, said inner wall being radially inwardly spaced from the outer wall to afford an annular air inlet duct leading approximately verticallyi downwardly 'into the outer peripheral portion 'of the oil well and providing wlthinthe connes of said inner wall an interior chamber of materially greater cross-sectional area than said annular air inlet passage, an outlet from the upper portion of the chamber, ldust and oil intercepting means horizontally spanning the interior of the chamber above the well, and an upstanding annular wall concentrically arranged within the oil well and being of less diameter than said inner wall, said upstanding wall upwardly terminating below the intercepting means and defining the inner side of a reversely directed annular continuation of said air inlet passage which leads from the oil well upwardly into the interior chamber and is of materially less cross-sectional area than said chamber, there being a radial passage of material circumferentially extent between the reversely directed portion oi said annular intake substantially at the normal static fluid level; whereby air directed downwardly into the oill well will depressA the oil level and reverse its direction over the oil in the well radially outward of the upstanding annular wall -in the oil well and against the outer surface of said upstanding wall, and will then expand over the upper edge of said upstanding wall into the interior chamber.

14. 'I'he structure defined in claim 13, in which v the said annular wall is provided with circumferentially spaced perforations intermediate its upper and lower edges. 

